Convector plates

ABSTRACT

A convector plate for use in heat treatment furnaces comprising a plate of substantially circular configuration with an upper and lower surface each of which includes a plurality of gas passage means of channel section, the passage means in one face being mutually parallel and each means in one face being mutually parallel and each having substantially parallel wall means, wherein the passage means in the upper surface are disposed mutually at right angles to the passage means in the lower surface.

United States Patent [151 3,661,37 1 Skelton et al. 51 May 9, 1972 s41 CONVECTOR PLATES [56] References Cited [72] inventors: Leslie George Victor Skelton, Port Talbot; UNITED STATES PATENTS Godfrey Hunt Thomas, Porthcawl; Hedley Brynmor Jenkins Port Talbot, a" f 3,415,506 12/1968 Blackman ..263/47 A Wales Assignee:

Wales Filed: May 12, 1970 Appl. No.: 36,559

Foreign Application Priority Data Skelton-Thomas Limited, Port Talbot,

May I3, 1969 Great Britain ..24,379/69 U.S. Cl ..266/5 R, 263/47 A Int. Cl.

Field of Search ..263/47 A; 266/5 R Primary Examiner-Gerald A. Dost An0rne v-Woodhams. Blanchard and Flynn [57] ABSTRACT 6 Claims, 6 Drawing Figures PATENTEDMAY 9 m2 3,6613 71 SHEET 1 [1F 3 CONVECTOR PLATES The invention relates to convector plates of the kind which are placed between vertically stacked metal coils in heat treatment furnaces, for example annealing furnaces. Such annealing furnaces generally incorporate an enclosing cover or hood,

' alternately with convector plates, on top of one another in the annealing furnace.

According to the invention there is provided a convector plate for use in heat-treatment furnaces comprising a plurality of gas passages extending across each face of the plate, the passages in one face being substantially parallel, and each gas passage having substantially parallel walls.

According to the invention furthermore there is provided, a convector plate for use in heat treatment furnaces which comprises a plurality of support members forming a grid which defines a set of substantially parallel gas passages extending across the plate.

Preferably there may be two sets of each face of the plate.

Furthermore, the total area of the gas passages in one face may amount to approximately 50 percent of the surface area of that face.

Suitably each support member may comprise a metal bar. The metal may be mild or cast steel or aluminum, or an alloy.

Also, one set of gas passages in one face may be at right angles to the set of gas passages in the other face.

The bars forming the grid may be arranged symmetrically to minimize distortion during operation and to minimize the.possibility of failure during repeated heating and cooling cycles within an annealing furnace. The plate may be approximately circular in shape, with a central orifice or vent which is also circular. A number of lugs, a central ring, or other convenient lifting means may be attached to the plate, depending on the handling equipment available. Thus two lugs may be secured to the support members so that they are diametrically disposed with respect to the vent, on the circumference of the vent. These lugs facilitate the use of lifting equipment for handling the convector plates into and out of the annealing furnace.

The invention is hereinafter described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 shows a plan view of an arrangement of base plates of one embodiment of convector plate;

FIG. 2 is a plan view of an arrangement of top plates of one embodiment of convector plate;

F IG. 3 shows a plan view of another embodiment of convector plate;

FIG. 4 shows a view in the direction of the arrow A in FIG.

gas passages, one in FIG. 5 shows a plan view of a further embodiment of convector plate; and

FIG. 6 shows a sectional view of part of an annealing furnace in which the convector plate of FIGS. 3, 4 or 5 is utilized.

A set 1 of base plates (FIG. 1) is of generally circular configuration and comprises a plurality of parallel fiat steel bars'2 of non-uniform width. Parallel air passages 3 are defined by the bars 2. Two central bars 4 are welded to a circular supporting ring 5 which is also welded to bars in the set 1 immediately adjacent the bars 4 on each side thereof.

Referring now to FIG. 2, a set 6 of top plates is also of generally circular configuration and comprises a plurality of parallel, flat steel bars 7 of varying widths. Two central pairs 8 of bars are welded to a support ring 9. The set 6 of bars defines a plurality of parallel air passages 10.

A convector plate according to the invention comprises a combination of the sets 1 and 6 of base and top plates, which are placed one on top of the other with their respective bars 2 and 7 at right angles to one another and with the two support rings 5 and 9 in verticalalignment. The two sets are then welded together to provide a rigid and stable structure having a central vent.

Referring now to FIGS. 3 and 4, a convector plate 11 illustrated therein is similar to that described above, with the modification that central bars l2, l3, l4 and 15 and the bars l6, l7, l8 and 19 are shaped to provide a central vent 20 in the plate 11.

A lifting lug 21 is secured between the bars 12 and 13, a diametrically opposed lug 22 being likewise secured to the bars 14 and 15.

Referring now to FIG. 5, a convector plate 23 similar to that described with reference to FIGS. 1 to 4, is illustrated, and includes four lifting lugs 24.

The bars maybe of mild steel, aluminum, or any suitable material depending onthe metal which is being treated in the annealing furnace utilizing the convector plates.

The bars may be of any convenient dimension, for example 6 inch wide and three-fourth inch thick.

In use, assuming the convector plate of FIG. 3 is being used, coils 25 of metal, which may be sheet steel are stacked one on top of the other in an annealing furnace X with the convector plate 11 separating each coil (see FIG. 6). An annealing or protective gas is circulated by a fan 26 through the furnace, which is maintained at a predetermined temperature. The gas passes down the air passages 3 and 10 into the central vent 20, from which it is recirculated. The parallel sides of the air passages ensure that the gas has an uninterrupted flow over the coils so that the rate of heat input by convection, conduction and radiation to the coils is increased. Also the annealing gas is able to pass to the center of the coils through the vent.

When the annealing cycle is complete, the coils and convector plates are removed from the furnace by engaging lifting tackle with the lifting ring or lugs.

It is to be understood that the non-uniform width of the bars is to accommodate differing widths of coils to be annealed, so that the entire peripheries of such coils are supported during the annealing treatment.

The convector plates according to the invention thus provide improved convection in the annealing furnace and an improvement in tons treated per hour of furnace use. It has also been found that the convector plates according to the invention result in a saving of three to four hours in cooling time per charge and an improvement in furnace performance, such as in fuel and HNX gas consumption, while a further desirable feature is that coil edge damage is reduced considerably due to the support afforded by the plates.

We claim:

1. A convector plate for use in heat treatment furnaces comprising a plate of substantially circular configuration with an upper and a lower surface, wherein the upper surface is defined by a plurality of spaced apart support members and the lower surface is defined by a plurality of spaced apart support members located mutually at right angles with the support members of the upper surface, the spaced apart support members of each surface defining a plurality of open passages for passage of gas.

2. A convector plate as claimed in claim 1, in which the open gas passages in one surface comprise 50 percent of the total surface area of that surface.

3. A convector plate for use in heat treatment furnaces comprising a plate of substantially circular configuration with an upper and a lower surface and central vent means, wherein the upper surface is defined by a plurality of spaced-apart support members and the lower surface is defined by a plurality of spaced-apart support members located mutually at right angles withthe support members of the upper surface, the spaced-apart support members of each surface defining a plurality of open passages for passage of gas.

4. A convector plate according to claim 3, in which diametrically opposed central gas passages in the upper and lower surface communicate directly with the vent means.

5. A convector plate according to claim 4, in which lifting means is secured at the periphery of the vent means.

6. A convector plate according to claim 5, in which the plurality of support members in each surface comprise metal bars of non-uniform width. 

1. A convector plate for use in heat treatment furnaces comprising a plate of substantially circular configuration with an upper and a lower surface, wherein the upper surface is defined by a plurality of spaced apart support members and the lower surface is defined by a plurality of spaced apart support members located mutually at right angles with the support members of the upper surface, the spaced apart support members of each surface defining a plurality of open pasSages for passage of gas.
 2. A convector plate as claimed in claim 1, in which the open gas passages in one surface comprise 50 percent of the total surface area of that surface.
 3. A convector plate for use in heat treatment furnaces comprising a plate of substantially circular configuration with an upper and a lower surface and central vent means, wherein the upper surface is defined by a plurality of spaced-apart support members and the lower surface is defined by a plurality of spaced-apart support members located mutually at right angles with the support members of the upper surface, the spaced-apart support members of each surface defining a plurality of open passages for passage of gas.
 4. A convector plate according to claim 3, in which diametrically opposed central gas passages in the upper and lower surface communicate directly with the vent means.
 5. A convector plate according to claim 4, in which lifting means is secured at the periphery of the vent means.
 6. A convector plate according to claim 5, in which the plurality of support members in each surface comprise metal bars of non-uniform width. 